Chapter 8 Introduction to Radiologic and Imaging Science and Patient Care

diagnostic yield

The AMOUNT of clinically useful information on a diagnostic image

radiography

Imaging modality more concerned with bones, physiology of GI tract, circulatory system

sonography

Imaging modality more concerned with blood flow, fluid in the body, babies

CT

Imaging modality more concerned with three dimensional look, contrast to see structures (organs and bones)

MRI

Imaging modality more concerned with soft tissue structure like ligaments and tendons

nuclear medicine

Imaging modality more concerned with inserting isotopes and seeing physiology

modality

each ______ has its own considerations for ordering the procedure

diagnostic efficacy

The ACCURACY of diagnostic information on a medical image

true

any extraneous information on an image that does not reflect the patient's ____ medical condition detracts from diagnostic efficacy

optimized

diagnostic efficacy and diagnostic yield must be _______ as the standard of care

xray machine design features

xray tube and support

collimator assembly

radiographic table

xray generator and control

upright image receptor

lead

xray tube is inside the _____-lined tube housing

vacuum

the xray tube is made of Pyrex glass with high ____

xray tube design

produces x-radiation while high-energy electricity passes through

housing

x-radiation exits the tube through a window in the ____ and is directed toward a patient

collimator

controls the size and shape of the xray field directed toward the patient

collimator

projects a high-intensity light field on the patient, which represents the area of the x-ray field of exposure

collimator

may be manual or PBL (positive beam limitation aka automatic)

oil

tube is incased in lead and lathered in ____ to absorb the heat

window

the opening in the lead container to focus the light

collimator

after the window of lead box around xray tube, there is an additional focus tool

radiographic table

may be fixed height or variable height (foot controlled)

radiographic table

typically has a four-way "floating" tabletop

radiolucent

radiographic table is highly ____

radiographic table

some designs permit a variable speed, titling capacities

fluorotable

which table is not floating and is "fixed"

tilting radiographic table

these designs will tilt the table from horizontal position to vertical upright position to trendelenburg

tilting radiographic table

most tables have four-way tabletop travel

tilting radiographic table

these tables typically do not have variable height capabilities

bucky

the tray built into a radiographic table/ or wall that holds the image receptor

bucky

consists of a receptor tray and radiographic grid

bucky

tray holds receptor tightly in position and is centered to longitudinal axis of table

bucky

where it is in relation to the table it does not change but can be moved under the patient to area where xray is needed

bucky

radiographic grid oscillates during exposure to blur out the lead grid line

bucky

when the light turns on, means tube is lined up with the ____

use buckies

film screen, flat panel DR

computed radiography

DR

these systems have replaced the cassette tray and moving grid with a STATIONARY grid and NO tray

oscillates

how does the grid get rid of the lead lines leaving a mark on the image?

control console

is the interface between the radiographer and the electrons of the xray machine

generator console

features include exposure technique selections as well as exposure button

control console

permits selection of all exposure factors

mAs

kVp

focal spot size

automatic exposure control

anatomical programming

exposure technique

consists of three key factors

mA

S

kVp

exposure technique

AEC may be optional

exposure technique

focal spot size selection

exposure technique

may be anatomically programmed

exposure technique

can be operated in mAs or timer mode

tube supports

two designs

ceiling mounted (more reach and mobility)

floor mounted (limited on mobility)

OTC

newer overhead tubecrane designs permit selection of exposure factors at the tubehead control, with a flat panel screen

OTC

digital radiography systems may display the image from the last exposure for review

OTC

autotracking feature permits synchronus movement of ___ and vertical upright holder

OTC

exposure requires the operator to be behind the control booth

film screen

CR

Image receptors that still use cassette

the only radiation that is of any clinical value

remnant radiation ABSORBED in the detector

remnant radiation is converted to an electrical signal, digitized, and sent to a computer for processing

finally presented as a radiographic image for interpretation

detectors

are expensive and must be treated with care (10k)

sensitive to mechanical shock

fluid invasion

fluoroscopy

requires special equipment designs that feature an xray tube with attached image receptor in a perpendicular relationship

Trendelenburg position

lying on back with body tilted so that the head is lower than the feet

c-arm fluoroscopy

used for interventional procedures

feature in a c-shape that moves xray tube with an image receptor

portable

need to be charged in between use

have parking spots

Mobile Fluoroscopy

used in surgery and interventional exams

uses c-arm design

image receptor is at a fixed SID and centered to xray tube

subtraction

uses a flat-panel digital detector

takes two back to back exposures (HIGH and LOW kVp)

computer takes both image and subtracts the bone leaving the vascular picture

DR systems use

thin-film transistors (TFTs)

DR systems use

Indirect digital detector technology

Direct digital detector technology

control console

most are microprocessor controlled and use a simple computer interface

control console

newer systems may be integrated into a DR detector

exposure technique selection

critical to good radiography